Building Regulations Part L Volume 2, 2021 Edition

Building Regulations Part L Volume 2, 2021 Edition

New energy efficiency standards for non-domestic buildings in England are due to come into effect on 15th June 2022. Building Regulations Part L, Volume 2: ‘Buildings other than dwelling’ (2021 edition) will introduce an uplift in standards with the aim of achieving a 27% reduction in carbon emissions over the current Part L2A 2013 regulations.

The uplift in standards will include a combination of building fabric and building service improvements, and low carbon technologies. The changes from current Part L2A 2013 regulations are summarised in this briefing note.

Key changes

Building Fabric

Fabric improvements will include the introduction of higher minimum standards for thermal performance (U-values) and air permeability, in comparison with current Part L2 2013. The proposed changes are shown in the table below [Approved Document, Section 4]:

Part L table 1

The improved building fabric standards will apply to new insulating elements in all of the following cases:

  • Elements in new buildings,
  • New elements in extension of existing buildings, and
  • New or replacement elements in existing buildings.

Building Services

For building services, Part L2 2021 will include the following changes:

  1. Increase in minimum efficiency standards for building services

Minimum efficiency standards improved across the board compared to the current values stated in the Non-domestic Building Services Guide.

Additionally new guidelines will be introduced around the sizing of building services to ensure that these match building demand more closely for greater efficiency. [Approved Document, Section 5 and 6]

2. Low carbon heating technologies

Heat pumps and heat networks will be prioritised over gas heating, and their low carbon benefits will be recognised in the NCM (National Calculation Methodology) for Part L2 through the introduction of a new carbon factors to align with the natural gas factor.

The NCM will also be updated to include solar PV in the notional (“baseline”) building, unless a heat pump is specified to meet 100% of the actual building’s space heat demand. This is intended to discourage excessive levels of solar PV in the actual building being used as a means of overcoming poor fabric performance.

3. Self-regulating devices

New regulations will be introduced to require that buildings must have self-regulating devices (e.g. TRVs, Thermostats, Room controllers) when a heating or cooling system is installed. [Approved Document, Section 5]

4. Building automation and control systems (BACS)

Introduction of a new requirement mandating for buildings that have a space heating or air conditioning system with an effective rated output over 180kW should be equipped with BACS. [Approved Document, Section 5]

5. Energy sub-metering for monitoring of as-built performance

Intention to continue to referencing CIBSE TM39 as the standard to which new buildings should be sub-metered. As well as meeting CIBSE TM39, the sub-metering installation should also enable a useful comparison to be made between design-stage energy forecasts, such as CIBSE TM54, and measured results (using a representative building archetype). [Approved Document, Section 5]

6. Lighting

Revised minimum efficacies for lighting installed in new non-domestic buildings to reflect improvements in LED lighting in recent years [Approved Document, Section 6]:

  • 95 luminaire lm/cW for general lighting; and
  • 80 luminaire lm/cW for display lighting.

The revised general lighting minimum will be beneficial for EPC calculations with ‘Shell’ lighting, where the minimum efficacy is currently set at 60 lm/cW.

7. Commissioning and handover

Commissioning requirements for new non-domestic buildings to be extended to cover both BACS, and on-site electricity generation systems.

Handover information must include a Building Log Book, Operating and Maintenance instructions for fixed building services, and Energy benchmarking information in accordance with CIBSE TM54 (buildings over 1,000 sqm). [Approved Document, Section 8 & 9]:

Demonstrating Compliance

To achieve Part L2 2021 compliance a newly constructed building must meet the following minimum energy performance requirements:

a) Target primary energy rate (TPER)

b) Target emission rate (TER)

The TPER compliance metric is a change from Part L2 2013, whereby new building compliance is measured only against the TER metric.

Primary energy is a reflection of how much raw fuel is used to generate a unit of final energy, from extraction to transportation to use. As such, renewable energy will perform well under primary energy metrics, especially when specified on-site.

The TPER metric will require a greater emphasis on reducing energy demand of the building, and in turn reduce consumption from grid supplied energy. This is expected to be achieved through a combination of fabric energy efficiency, efficient building services, and low and zero carbon technologies.

The Approved Document L (2021) notes that “the TPER and TER are not likely to be met by using the minimum standards for fabric”. This will be an adjustment for the typical base build warehouse development, as currently use of minimum building fabrics standards is common practice.

Transitional Arrangements

Transitional arrangements will apply between now and the introduction of Building Regulations Part L2 2021 on 15th June 2022. This is to provide developers with certainty on the version of Part L2 to which they must design and build.

The transitional arrangements allow the current Building Regulations L2 2013 to be applied, subject to the following conditions:

  • A building notice or an initial notice has been given to, or full plans deposited with, a local authority before 15th June 2022.
  • Works under the building notice/ initial notice/ full plans have already commenced, or commences within 12 months of the Part L 2021 coming into effect (June 2022)

The transitional arrangement timeline before and after 15th June 2022 is summarised below:

Part L table nr2


Approved Document L, Conservation of fuel and power. Volume 2: Buildings other than dwellings. 2021 edition (England)

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